James Webb Space Telescope discovers four of the oldest galaxies in the universe

New News, Jakarta – The James Webb Space Telescope (JWST) has detected four of the oldest galaxies in the known universe, which are forming stars much more rapidly than previously thought.

The four most distant galaxies ever seen are located a little over 13 billion light years from Earth. This means astronomers are seeing what galaxies looked like 300 to 500 million years after the Big Bang, at the beginning of the universe’s life that is now almost 14 billion years old, according to two new studies published April 4 in the journal Nature Astronomy.

“The frontier is advancing almost every month,” said Pieter van Dokkum, an astronomy professor at Yale University who was not involved in the study, in a commentary published in Nature Astronomy.

There is now only “300 million years of unexplored universe history between these galaxies and the Big Bang,” van Dokkum added.

This may sound like familiar news, as several recent studies have claimed the possible detection of older galaxies using JWST in recent months.

However, these four newly discovered galaxies are different – ​​astronomers have actually confirmed that they are truly ancient and not another celestial body or a closer galaxy masquerading as a more distant one.

For nearby galaxies, astronomers typically use color to estimate redshift, the parameter that describes the distance at which light waves stretch and turn red as they pass through the expanding universe.

However, this technique is a more difficult choice when exploring new territory as researched with JWST. In what van Dokkum describes as a “remarkable technique,” the authors of the new study used detailed measurements of galaxies’ spectra, or the range of light they emit at different frequencies, to double-check redshift accuracy.

These four galaxies existed during the reionization epoch, when astronomers thought the first stars were forming. After confirming the age of the galaxies, the researchers looked at the stars in the galaxies, and found that they were quite small, at least compared to our Milky Way.

However, these galaxies are also forming stars at a fast rate, something that was “surprising in the early universe,” said study co-author Stéphane Charlot, a researcher at

The Paris Institute of Astrophysics, says the four galaxies are in an epoch of reionization, when astronomers believe the first stars were forming. After confirming the age of the galaxies, the researchers measured the sizes of the stars in them and found that they are quite small when compared to our Milky Way. However, these galaxies are also forming stars at a very high rate – something that was “remarkable at the beginning of the universe,” said Charlot.

The galaxies also don’t contain very complex elements, indicating that their stars haven’t had time to create the heavier elements made of the original hydrogen and helium atoms from the early universe, according to the researchers.

“Galaxies must grow rapidly,” wrote van Dokkum, referring to the 300 million years in which these ancient galaxies formed. “To give you an idea of ​​this time, sharks have been around much longer!”

When JWST launches in December 2021, astronomers hope the telescope will find the first galaxies – but results like these suggest that galaxies may have started earlier than previously thought.